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Transcriptional Responses Associated with Virulence and Defence in the Interaction between Heterobasidion annosum s.s. and Norway Spruce.

Lundén K, Danielsson M, Durling MB, Ihrmark K, Nemesio Gorriz M, Stenlid J, Asiegbu FO, Elfstrand M - PLoS ONE (2015)

Bottom Line: Three delta-12 fatty acid desaturase transcripts and one Clavaminate synthase-like transcript, both associated with virulence in other pathosystems, were found among the significantly induced transcripts.Even in a small data set like ours, five novel highly expressed Norway spruce transcripts without significant alignment to any previously annotated protein in Genbank but present in the P. abies (v1.0) gene catalogue were identified.Therefore a more complete survey of the transcriptional responses in the interactions between Norway spruce and its major pathogen H. annosum would probably provide a better understanding of gymnosperm defence than accumulated until now.

View Article: PubMed Central - PubMed

Affiliation: Department of Forest Mycology and Plant Pathology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden.

ABSTRACT
Heterobasidion annosum sensu lato is a serious pathogen causing root and stem rot to conifers in the northern hemisphere and rendering the timber defective for sawing and pulping. In this study we applied next-generation sequencing to i) identify transcriptional responses unique to Heterobasidion-inoculated Norway spruce and ii) investigate the H. annosum transcripts to identify putative virulence factors. To address these objectives we wounded or inoculated 30-year-old Norway spruce clones with H. annosum and 454-sequenced the transcriptome of the interaction at 0, 5 and 15 days post inoculation. The 491,860 high-quality reads were de novo assembled and the relative expression was analysed. Overall, very few H. annosum transcripts were represented in our dataset. Three delta-12 fatty acid desaturase transcripts and one Clavaminate synthase-like transcript, both associated with virulence in other pathosystems, were found among the significantly induced transcripts. The analysis of the Norway spruce transcriptional responses produced a handful of differentially expressed transcripts. Most of these transcripts originated from genes known to respond to H. annosum. However, three genes that had not previously been reported to respond to H. annosum showed specific induction to inoculation: an oxophytodienoic acid-reductase (OPR), a beta-glucosidase and a germin-like protein (GLP2) gene. Even in a small data set like ours, five novel highly expressed Norway spruce transcripts without significant alignment to any previously annotated protein in Genbank but present in the P. abies (v1.0) gene catalogue were identified. Their expression pattern suggests a role in defence. Therefore a more complete survey of the transcriptional responses in the interactions between Norway spruce and its major pathogen H. annosum would probably provide a better understanding of gymnosperm defence than accumulated until now.

No MeSH data available.


Expression pattern of selected transcripts in an independent Norway spruce material compared to the RNAseq frequency data.Isotig01779, beta-glucosidase (a); isotig04668 GLP2 (b); isotig00380, OPR-like (c); contig00509, isoflavone reductase-like (d); isotig06030, ns-LTP (e) and isotig06890, hin1-like (f). The columns indicate relative expression levels over the control, determined with qPCR, for each time point and treatments. The bars indicate the standard error (SE) and superscript letters indicate significant differences between treatments (P<0.05, Kruskal-Wallis test with Dunn´s post test), N = 3. The circles indicate the basemean data reported by DEseq, where shaded symbols were significantly different from un-treated bark.
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pone.0131182.g003: Expression pattern of selected transcripts in an independent Norway spruce material compared to the RNAseq frequency data.Isotig01779, beta-glucosidase (a); isotig04668 GLP2 (b); isotig00380, OPR-like (c); contig00509, isoflavone reductase-like (d); isotig06030, ns-LTP (e) and isotig06890, hin1-like (f). The columns indicate relative expression levels over the control, determined with qPCR, for each time point and treatments. The bars indicate the standard error (SE) and superscript letters indicate significant differences between treatments (P<0.05, Kruskal-Wallis test with Dunn´s post test), N = 3. The circles indicate the basemean data reported by DEseq, where shaded symbols were significantly different from un-treated bark.

Mentions: A small subset of transcripts was selected for verification of the RNAseq data by qPCR analysis in independent Norway spruce genotypes. As predicted by the RNAseq data, isotig01779 and isotig04668 showed higher expression in the inoculated samples than wounded alone at both 5 and 15 dpi (Fig 3a and 3b). RNAseq data predicted a significant induction of contig00509 and isotig00380 in response to inoculation at 15 dpi; this was was observed for both transcripts (Fig 3c and 3d). However, isotig00380 also showed significant induction at 5 dpi (Fig 3c) and contig00509 was induced in response to wounding at 15 dpi (Fig 3d). According to the RNAseq data, isotig06030 (type1 nsLTP) was highly expressed but showed no differential expression between treatments, which was validated by qPCR (Fig 3e). Isotig06890 (Hin1-like) was expected to be expressed at low levels but without significant regulation, and was corroborated by qPCR data at 5 dpi. However at 15 dpi significant induction were seen in both wounded and inoculated samples (Fig 3f).


Transcriptional Responses Associated with Virulence and Defence in the Interaction between Heterobasidion annosum s.s. and Norway Spruce.

Lundén K, Danielsson M, Durling MB, Ihrmark K, Nemesio Gorriz M, Stenlid J, Asiegbu FO, Elfstrand M - PLoS ONE (2015)

Expression pattern of selected transcripts in an independent Norway spruce material compared to the RNAseq frequency data.Isotig01779, beta-glucosidase (a); isotig04668 GLP2 (b); isotig00380, OPR-like (c); contig00509, isoflavone reductase-like (d); isotig06030, ns-LTP (e) and isotig06890, hin1-like (f). The columns indicate relative expression levels over the control, determined with qPCR, for each time point and treatments. The bars indicate the standard error (SE) and superscript letters indicate significant differences between treatments (P<0.05, Kruskal-Wallis test with Dunn´s post test), N = 3. The circles indicate the basemean data reported by DEseq, where shaded symbols were significantly different from un-treated bark.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4495060&req=5

pone.0131182.g003: Expression pattern of selected transcripts in an independent Norway spruce material compared to the RNAseq frequency data.Isotig01779, beta-glucosidase (a); isotig04668 GLP2 (b); isotig00380, OPR-like (c); contig00509, isoflavone reductase-like (d); isotig06030, ns-LTP (e) and isotig06890, hin1-like (f). The columns indicate relative expression levels over the control, determined with qPCR, for each time point and treatments. The bars indicate the standard error (SE) and superscript letters indicate significant differences between treatments (P<0.05, Kruskal-Wallis test with Dunn´s post test), N = 3. The circles indicate the basemean data reported by DEseq, where shaded symbols were significantly different from un-treated bark.
Mentions: A small subset of transcripts was selected for verification of the RNAseq data by qPCR analysis in independent Norway spruce genotypes. As predicted by the RNAseq data, isotig01779 and isotig04668 showed higher expression in the inoculated samples than wounded alone at both 5 and 15 dpi (Fig 3a and 3b). RNAseq data predicted a significant induction of contig00509 and isotig00380 in response to inoculation at 15 dpi; this was was observed for both transcripts (Fig 3c and 3d). However, isotig00380 also showed significant induction at 5 dpi (Fig 3c) and contig00509 was induced in response to wounding at 15 dpi (Fig 3d). According to the RNAseq data, isotig06030 (type1 nsLTP) was highly expressed but showed no differential expression between treatments, which was validated by qPCR (Fig 3e). Isotig06890 (Hin1-like) was expected to be expressed at low levels but without significant regulation, and was corroborated by qPCR data at 5 dpi. However at 15 dpi significant induction were seen in both wounded and inoculated samples (Fig 3f).

Bottom Line: Three delta-12 fatty acid desaturase transcripts and one Clavaminate synthase-like transcript, both associated with virulence in other pathosystems, were found among the significantly induced transcripts.Even in a small data set like ours, five novel highly expressed Norway spruce transcripts without significant alignment to any previously annotated protein in Genbank but present in the P. abies (v1.0) gene catalogue were identified.Therefore a more complete survey of the transcriptional responses in the interactions between Norway spruce and its major pathogen H. annosum would probably provide a better understanding of gymnosperm defence than accumulated until now.

View Article: PubMed Central - PubMed

Affiliation: Department of Forest Mycology and Plant Pathology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden.

ABSTRACT
Heterobasidion annosum sensu lato is a serious pathogen causing root and stem rot to conifers in the northern hemisphere and rendering the timber defective for sawing and pulping. In this study we applied next-generation sequencing to i) identify transcriptional responses unique to Heterobasidion-inoculated Norway spruce and ii) investigate the H. annosum transcripts to identify putative virulence factors. To address these objectives we wounded or inoculated 30-year-old Norway spruce clones with H. annosum and 454-sequenced the transcriptome of the interaction at 0, 5 and 15 days post inoculation. The 491,860 high-quality reads were de novo assembled and the relative expression was analysed. Overall, very few H. annosum transcripts were represented in our dataset. Three delta-12 fatty acid desaturase transcripts and one Clavaminate synthase-like transcript, both associated with virulence in other pathosystems, were found among the significantly induced transcripts. The analysis of the Norway spruce transcriptional responses produced a handful of differentially expressed transcripts. Most of these transcripts originated from genes known to respond to H. annosum. However, three genes that had not previously been reported to respond to H. annosum showed specific induction to inoculation: an oxophytodienoic acid-reductase (OPR), a beta-glucosidase and a germin-like protein (GLP2) gene. Even in a small data set like ours, five novel highly expressed Norway spruce transcripts without significant alignment to any previously annotated protein in Genbank but present in the P. abies (v1.0) gene catalogue were identified. Their expression pattern suggests a role in defence. Therefore a more complete survey of the transcriptional responses in the interactions between Norway spruce and its major pathogen H. annosum would probably provide a better understanding of gymnosperm defence than accumulated until now.

No MeSH data available.